The present invention is directed to an adjustable tool, and more particularly to a selectively biased tool and methods of using the same.
A conventional gun reamer tool includes a cutting blade and one or more support members which are supported at intervals around the circumference of a rotary shaft (e.g., the reamer head). The shaft, along with the blade and the support members, rotate so that the physical interference between the rotating blade and the workpiece cause a hole to be either bored or reamed in the workpiece. During this machining operation, the rotating support members are positioned so that they support the inside surface of the hole being machined (e.g., either reamed or bored) by constraining radially directed motion of the blade relative to the workpiece.
In some conventional machining center rotating machine tools, lubricant is supplied to the vicinity of the cutting blade through the rotating shaft. An example is shown in U.S. Pat. No. 5,775,853 issued on Jul. 7, 1998, the disclosure of which is herein incorporated by reference.
This support and constraint supplied by the support members help to control the shape (e.g., cylindricity or circularity) of the hole, and help to maintain a constant alignment of the central axis of the hole along the length of the hole (in other words, the hole is straighter). For this reason, gun reamers are often used in applications where holes need to be precisely and accurately machined. Such precision applications may also be needed in the manufacture of automobile parts such as cylinder bores in engine blocks, connecting rod bores and piston wrist pin bores.
Gun reamers are also especially useful where the hole being cut is relatively long (such as the bore of a gun barrel), because the support members will remain in the proximity of the cutting blade, even when the blade has cut a long distance into the workpiece.
One potential shortcoming of conventional gun reamers is that they cannot be adjusted to cut holes of different sizes. Most conventional gun reamers are designed with support and blade members rigidly constrained to the reamer head so that the head can cut holes of just one predetermined radius. Another potential shortcoming of conventional gun reamers is that the blade and support members wear at different rates, which can cause seizure or variation in the diameter and/or circularity of the holes cut by the gun reamer.
In most machine tool operations, including boring and reaming, the friction between the tool and workpiece generates tremendous amounts of heat energy, which can reach temperatures of 2000xc2x0 F. (1100xc2x0 C.) and above. If left uncontrolled, such heat could severely damage (e.g., cracking or fracturing) the tool, thus reducing its tool life, making machine tool operations more dangerous and expensive, and reducing the quality and precision of the workmanship. In addition, heat generated friction can discolor the workpiece, and can damage or remove temper or heat treatments. It is commonly known in the industry that coolant can be introduced to the machining area, such as by spraying, to reduce friction between the tool and workpiece by providing coolant fluid between the cutting tool and the workpiece, and to help remove heat energy generated in machine tool operations.
Although coolant fluid can be supplied to the machining area, it is often difficult to insure that such fluid actually makes its way to the interstices between the tool and all of the workpiece surfaces being machined. Additionally, fluid can evaporate quickly due to the high temperatures involved in machining operations. Thus, larger volumes of coolant fluid must generally be continuously supplied to the machining area for the tool to operate effectively. This need to keep coolant fluid between the tool and wall of the bore hole becomes even more problematic in operations where coolant fluids cannot be introduced in close proximity to the machining areas while the tool is engaged with the interior surface of the workpiece.
During use, the work engaging surface of the tool (e.g., the cutting blade and/or support member) can also become loaded with particles or recently cut chips from the interior surface of the workpiece, which in turn, reduces the accuracy and effectiveness of the tool through deteriorating machining ability, and/or clogging of conventional coolant fluid supply openings. It is obviously preferred that the potential for this undesired loading of particles be reduced, and that any loaded particles be removed from the tool as quickly as possible. Typically, nozzle arrangements, such as an external cleaning jet, are provided independent of the tool, for injecting coolant fluid at increased velocities toward the work engaging surface and the work surfaces of the workpiece to wash away particles, to remove particles already loaded on the work surface, and to cool the tool and the workpiece. As mentioned before, it is often very difficult to insure that the fluid sprayed in this way actually reaches the most critical areas of the tool/workpiece interface.
Other attempts to deliver coolant fluid to the machining area have included air or other pneumatic carriers. As with externally applied liquid coolants, when pneumatic carriers are used, resulting turbulence can hinder the machining operations, and often fluid cannot infiltrate into the actual machining area. Previously, attempts to address these two requirements of cooling and cleaning the tool and workpiece have tended to reduce the accuracy and utility of the tool.
As can be seen, currently available tools have a number of shortcomings that can greatly reduce the accuracy of the tools, the tool""s life, and its ability to use these tools with automatic tool changing systems. The current structures and assemblies provide a tool having working surfaces that cannot expand to accommodate varying and different uses and needs. Such assemblies can result in uneven machining, and reduces the assembly""s usable life. A need currently exists in the machinery industry for a tool with a work engaging assembly having accurately controlled machining diameters so that holes of different sizes can be cut, so that tools cannot become oversized a result of excessive strokes of the tools, and so that the tool can expand in a radial direction uniformly and selectively.
It is an object of the present invention to provide a cutting tool that addresses and overcomes the above-mentioned shortcomings and problems in the machine tool industry.
It is another object of the present invention to provide a cutting tool with support members to support a workpiece, where the support member and/or a blade member are selectively biased.
It is another object of the present invention to provide a cutting tool whereby the relative position of the blade and the workpiece can be controlled by the selective control of the bias of the blade member and/or support member.
It is yet another object of the present invention to provide a cutting tool that has an increased tool life.
It is also an object of the present invention to provide a tool that eliminates the need for external coolant fluid jets for cleaning or removing loaded particles from the tool""s machining surface during use, and routes fluid in close proximity to the work engaging surface to wash away recently cut particles.
It is yet another object of the present invention to provide a tool where the workload is reliably distributed over substantially the entire work engaging surface.
It is another object of the present invention to provide a tool for accurately and uniformly machining a workpiece.
It is further an object of the present invention to provide a tool that can be selectively adjusted during machine operations.
Yet another object of the present invention is to provide a tool that can compensate for material deformation in a workpiece.
It is still another object of the present invention to provide a tool in which coolant fluid delivery to the working area is not inhibited while the tool is engaged with a surface of the workpiece.
A further object of the present invention is to provide a tool that can compensate for wear and tear.
It is yet an object of the present invention to provide a tool that can be used with a quick change or automatic changeable tool system having a fluid pressure source.
Still another object of the present invention is to provide a tool that can be used to machine holes of different or varying diameters.
It is a further object of the present invention to provide a tool that continuously, selectively, and controllably delivers coolant fluid to the machining area despite the type of tool engagement.
Yet another object of the present invention is to provide a tool which self regulates itself for wear and tear on the abrasive.
Still a further object of the present invention is to provide a device where the work engaging surface can be uniformly varied in a radial direction by selectively applying fluid pressure.
A further object of the present invention is to provide a tool that dissipates thermal energy generated in the machining operations, and reduces thermal expansion of the tool.
Additional objects, advantages and other features of the invention will be set forth and will become apparent to those skilled in the art upon examination of the following, or may be learned with practice of the invention.
In some exemplary embodiments of the present invention, the support member and/or blade member of the cutting tool can be selectively biased by selecting the fluid pressure of a fluid which bears on the support member and/or blade member. For example, the tool may be constructed so that pressurized lubricating fluid, which is supplied near or in the vicinity of the cutting blade, bears on and biases both the blade member and the support member. As another exemplary alternative, the blade member and/or the support member may be selectively biased by air pressure and/or by one or more springs.
In some exemplary embodiments of the present invention, the tool is a reamer which has at least one support member and a blade member, such as a blade cartridge, biased by selectively pressurized fluid. It is an advantage of these exemplary reamer embodiments that the fluid pressure can be selected to compensate for wear of the blade, and also to compensate for the difference in wear between the blade and the support member.
In some exemplary embodiments of the present invention, the tool is a reamer where both the blade member and the support members are biased by selectively pressurized fluid. In these exemplary reamer embodiments, the fluid pressure can be selected to control the diameter of the hole so that a single reamer can ream holes of different diameters. Also, the fluid pressure can be selected to compensate for wear of the cutting blade. Also, the fluid pressure can be selectively controlled as the hole is being reamed to control the longitudinal profile of the hole, or to compensate for workpiece deformation which can occur as the hole is reamed.
In another exemplary embodiment, the tool includes a working portion with a working member, a side surface and an end surface. The working portion includes a passage passing through the side surface and the end surface. The tool further includes at least one seal adapted to restrict fluid flow through the side surface and the end surface and at least partially defining a pressure chamber. The working member is adapted to be selectively pivotally positioned to any of a variety of working positions in use by selectively pressurizing the pressure chamber.
Still another exemplary embodiment of the invention involves a method of removing material from a workpiece. With such method, a tool is provided including a working portion with a working member. Fluid pressure is provided to pivot the working member outwardly to at least one of a plurality of alternative use positions. The tool is then moved towards the workpiece such that the working member selectively removes material from the workpiece as the working member is applied to the workpiece. It will be understood that the tool can be moved before, during and/or after adjustment of the working member to the use position.
Still other objects of the present invention will become readily apparent to those skilled in this art from the following description wherein there is shown and described an exemplary embodiment of this invention, simply by way of illustration, of one of the best modes contemplated for carrying out this invention. As will be realized, the invention is capable of other different embodiments, and its several details are capable of modification in various aspects all without departing from the invention. Accordingly, the drawings and descriptions will be regarded as illustrative in nature, and not as restrictive.